Triazinyl-organophosphorus esters

ABSTRACT

Organophosphorus esters of the formula (I), ##STR1## wherein R is a C 1  -C 2  alkyl group, R 1  is a C 1  -C 2  alkyl, C 1  -C 2  alkoxy, C 1  -C 4  alkylamino, phenyl or phenoxy group, R 2  and R 3 , which may be the same or different, are each a C 1  -C 5  alkyl or methoxy C 2  -C 3  alkyl group and X is an oxygen or sulfur atom, a method for producing organophosphorus esters of the formula (I) characterized by condensation reaction of s-triazines of the formula, ##STR2## wherein M is a potassium or sodium atom and R 2  and R 3  are as defined above, with a halogenated compound of the formula, ##STR3## wherein Y is a halogen atom and R, R 1  and X are as defined above, and an insecticide, acaricide and/or nematocide characterized by containing organophosphorus esters of the formula (I) as an active ingredient.

The present invention relates to novel organophosphorus esters, theirproduction and an insecticide, acaricide and/or nematocide characterizedby containing them as an active ingredient.

More particularly, the present invention relates to (1) organophosphorusesters of the formula (I), ##STR4## wherein R is a C₁ -C₂ alkyl group,R₁ is a C₁ -C₂ alkyl, C₁ -C₂ alkoxy, C₁ -C₄ alkylamino, phenyl orphenoxy group, R₂ and R₃, which may be the same or different, are each aC₁ -C₅ alkyl or methoxy C₂ -C₃ alkyl group and X is an oxygen or sulfuratom, (2) a method for producing organophosphorus esters of the formula(I) characterized by the condensation reaction of s-triazines of theformula (II), ##STR5## wherein R₂ and R₃ are as defined above, and M isa potassium or sodium atom, preferably a potassium atom, with ahalogenated compound of the formula (III), ##STR6## wherein R, R₁ and Xare as defined above, and Y is a halogen atom (chlorine, bromine,fluorine and iodine), and (3) an insecticide, acaricide and/ornematocide characterized by containing organophosphorus esters of theformula (I), ##STR7## wherein R, R₁, R₂, R₃ and X are as defined above,as an active ingredient.

The compounds of the present invention represented by the formula (I)are novel compounds, and some examples of the compounds will be shownhereinafter. But the present invention is not of course limited to theseexamples.

    ______________________________________                                        Com-                                                                          pound                          Physical                                       No.   Chemical structure       constant                                       ______________________________________                                        (1)                                                                                  ##STR8##                n.sub.D.sup.25.0  1.5011                       (2)                                                                                  ##STR9##                n.sub.D.sup.20.0  1.4824                       (3)                                                                                  ##STR10##               n.sub.D.sup.21.7  1.4670                       (4)                                                                                  ##STR11##               n.sub.D.sup.21.0  1.5167                       (5)                                                                                  ##STR12##               n.sub.D.sup.19.0  1.4972                       (6)                                                                                  ##STR13##               n.sub.D.sup.20.0  1.5582                       (7)                                                                                  ##STR14##               n.sub.D.sup.20.0  1.5455                       (8)                                                                                  ##STR15##               n.sub.D.sup.20.0  1.5030                       (9)                                                                                  ##STR16##               n.sub.D.sup.25.5  1.4970                       (10)                                                                                 ##STR17##               n.sub.D.sup.25.5  1.4977                       (11)                                                                                 ##STR18##               n.sub.D.sup.25.5  1.4968                       (12)                                                                                 ##STR19##               n.sub.D.sup.21.5  1.4996                       (13)                                                                                 ##STR20##               n.sub.D.sup.21.5   1.4920                      (14)                                                                                 ##STR21##               n.sub.D.sup.21.5  1.5420                       (15)                                                                                 ##STR22##               n.sub.D.sup.21.5  1.5162                       (16)                                                                                 ##STR23##               n.sub.D.sup.23.0  1.4940                       (17)                                                                                 ##STR24##               n.sub.D.sup.23.0  1.4900                       (18)                                                                                 ##STR25##               n.sub.D.sup.22.5 1.5410                        (19)                                                                                 ##STR26##               n.sub.D.sup.26.0  1.5165                       (20)                                                                                 ##STR27##               n.sub.D.sup.24.5  1.5109                       (21)                                                                                 ##STR28##               n.sub.D.sup.23.5 1.5065                        (22)                                                                                 ##STR29##               n.sub.D.sup.23.5 1.5068                        (23)                                                                                 ##STR30##               n.sub.D .sup.22.0  1.4991                      (24)                                                                                 ##STR31##               n.sub.D.sup.22.0  1.4945                       (25)                                                                                 ##STR32##               n.sub.D.sup.25.5  1.4975                       (26)                                                                                 ##STR33##               n.sub.D.sup.23.5 1.5085                        (27)                                                                                 ##STR34##               n.sub.D.sup.21.0 1.4968                        (28)                                                                                 ##STR35##               n.sub.D.sup.23.0 1.4845                        (29)                                                                                 ##STR36##               n.sub.D.sup.20.0 1.5281                        (30)                                                                                 ##STR37##               n.sub.D.sup.26.0 1.4840                        (31)                                                                                 ##STR38##               n.sub.D.sup.24.0 1.5293                        (32)                                                                                 ##STR39##               n.sub.D.sup.22.0 1.4601                        (33)                                                                                 ##STR40##               n.sub.D.sup.26.0 1.4723                        (34)                                                                                 ##STR41##               n.sub.D.sup.26.0 1.5220                        (35)                                                                                 ##STR42##               n.sub.D.sup.26.0 1.4770                        (36)                                                                                 ##STR43##               n.sub.D.sup.26.0 1.5127                        (37)                                                                                 ##STR44##               n.sub.D.sup.24.5 1.4954                        (38)                                                                                 ##STR45##               n.sub.D.sup.27.0 1.5421                        (39)                                                                                 ##STR46##               n.sub.D.sup.24.5 1.4902                        (40)                                                                                 ##STR47##               n.sub.D.sup.29.0 1.4640                        (41)                                                                                 ##STR48##               n.sub.D.sup.29.0 1.4593                        ______________________________________                                    

The compounds of the present invention can be obtained with satisfactoryresults by reacting s-triazines (II) with a halogenated compound (III)in an amount of 0.9 to 1.0 time by mole based on the s-triazines at atemperature of from about 0° C. to about 100° C. for 1 to 10 hours withstirring in a solvent and if necessary in the presence of 0.1 to 10 mole% of copper powder, cuprous chloride or a phase transfer catalyst (e.g.quaternary ammonium salts, phosphonium salts, crown ethers). The solventincludes for example ketones (e.g. acetone, methyl isobutyl ketone),acetonitrile, benzene, toluene and water. After completion of thereaction, the objective compounds can be isolated by the usualafter-treatments, and if necessary they may further be purified bydistillation or chromatography on silica gel.

Some examples of s-triazines and halogenated compounds, startingmaterials of the present compounds, will be shown hereinafter.

    ______________________________________                                        s-Triazines:                                                                  ______________________________________                                        Potassium 2,4-dimethoxy-s-                                                    triazin-6-olate     (known compound)                                          Potassium 2,4-diethoxy-s-                                                                         (novel compound but its                                   triazin-6-olate     free acid is known)                                       Potassium 2,4-di-n-propoxy-                                                                       (novel compound but its                                   s-triazin-6-olate   free acid is known)                                       Potassium 2,4-di-isopropoxy-s-                                                triazin-6-olate     (novel compound)                                          Potassium 2,4-di-n-butoxy-s-                                                  triazin-6-olate     (novel compound)                                          Potassium 2,4-di-isobutoxy-s-                                                 triazin-6-olate     (novel compound)                                          Potassium 2,4-di-sec-butoxy-s-                                                triazin-6-olate     (novel compound)                                          Potassium 2,4-di-n-pentyloxy-s-                                               triazin-6-olate     (novel compound)                                          Potassium 2,4-di-isopentyloxy-s-                                              trizin-6-olate      (novel compound)                                          Potassium 2,4-bis(methoxyethoxy)-                                             s-triazin-6-olate   (novel compound)                                          Potassium 2,4-bis(β-methoxy-                                             isopropoxy)-s-triazin-6-olate                                                                     (novel compound)                                          Sodium 2,4-bis(β-methoxy-                                                isopropoxy)-s-triazin-6-olate                                                                     (novel compound)                                          Potassium 2,4-bis(allyloxy)-                                                  s-triazin-6-olate   (novel compound)                                          ______________________________________                                    

Halogenated compound:

Ethyl phenylphosphonochloridothionate

O,O-dimethyl phosphorochloridothionate

O,O-diethyl phosphorochloridothionate

O-ethyl O-phenylphosphorochloridothionate

O-methyl N-methylphosphoramidochloridothionate

O-methyl N-ethylphosphoramidochloridothionate

O-methyl N-n-propylphosphoramidochloridothionate

O-methyl N-isopropylphosphoramidochloridothionate

O-methyl N-n-butylphosphoramidochloridothionate

O-methyl N-isobutylphosphoramidochloridothionate

O-methyl N-sec-butylphosphoramidochloridothionate

O-ethyl N-methylphosphoramidochloridothionate

O-ethyl N-ethylphosphoramidochloridothionate

O-ethyl N-n-propylphosphoramidochloridothionate

O-ethyl N-isopropylphosphoramidochloridothionate

O-ethyl N-n-butylphosphoramidochloridothionate

O-ethyl N-isobutylphosphoramidochloridothionate

O-ethyl N-sec-butylphosphoramidochloridothionate

O,O-dimethyl phosphorochloridate

O,O-diethyl phosphorochloridate

O,O-diethyl phosphorobromidate

The halogenated compounds described above can by synthesized by themethods disclosed in the following literatures:

K. Sasse, Organische Phosphorverbindungen, in Methoden der OrganischenChemie, Vol XII/1. Muller, Ed., Georg Thieme Verlag, Stuttgart, 1963

K. Sasse, Organische Phosphorverbindungen, in Methoden der OrganischenChemie, Vol XII/2. Muller, Ed., Georg Thieme Verlag, Stuttgart, 1964

Insecticides, acaricides and nematocides have made a great contributionto remarkably increase agricultural production through their controllingeffects against various harmful insects parasitic on agricultural crops.However, various problems such as toxicity to mammals and pollution ofnatural environment have appeared to develop to such a degree that theuse of effective insecticides, acaricides and nematocides is feared insome fields.

For the reasons as described above, there is a strong demand for thedevelopment of insecticides, acaricides and nematocides which are low intoxicity, free from fear of environmental pollution and effective incontrolling harmful insects.

As a result of extensive study to develop excellent insecticides,acaricides and nematocides satisfying the above requirements, theinventors found that the present compounds of the formula (I) haveproperties meeting the above requirements, and thus completed thepresent invention. The present compounds of the formula (I) areparticularly suitable for controlling stem-borers, planthoppers,leafhoppers and bugs in paddy field; insects doing damage to vegetables,fruit trees and wood, for example insects belonging to Lepidoptera [e.g.diamondback moth (Plutella xylostella), armyworms and cutworms,tortorixes] and Orthoptera (e.g. grasshoppers); mites, nematodes anddisease-carrying mosquitoes, flies, cockroaches, ticks, fleas and lice;and insects harmful to stored cereals.

In the practical application of the present compounds, they may beapplied alone without other components or in mixtures with carriers forease of use as controlling agents. The commonly used preparation forms,for example emulsifiable concentrates, wettable powders, dusts,granules, fine granules, oil sprays, aerosols and baits, can be producedoptionally, with no need of particular conditions, by the methods wellknown to those skilled in the art according to the methods for producingcommon agricultural chemicals. The compounds of the present inventioncan be applied to various usages in required preparation forms and withrequired carriers. The foregoing preparations generally contain 0.1 to95% by weight of active ingredient (including other ingredients mixed).

Further, multi-purpose compositions of excellent efficacy can beproduced by mixing with other active ingredients, for example,organo-phosphorus insecticides such as O,O-dimethylO-(3-methyl-4-nitrophenyl)phosphorothioate (hereinafter referred to asSumithion, a registered trade mark of Sumitomo Chemical Co.) andO,O-dimethyl O-(2,2-dichlorovinyl)phosphate (hereinafter referred to asDDVP); carbamate insecticides such as 1-naphthyl N-methylcarbamate,3,4-dimethylphenyl N-methylcarbamate and 3,5-dimethylphenylN-methylcarbamate; Allethrin, 3,4,5,6-tetrahydrophthalimidomethylchrysanthemate (hereinafter referred to as tetramethrin),5-benzyl-3-furylmethyl chrysanthemate (hereinafter referred to asChrysron, a registered trade mark of Sumitomo Chemical Co.); otherinsecticides such as B.T., fungicides, nematocides, acaricides,herbicides, insect hormone compounds, other agricultural chemicals andfertilizers. Further, a synergistic effect can be expected by suchmixing.

The present invention will be illustrated in more detail with referenceto the following examples and preparation examples.

EXAMPLE 1 (Compound No. 1)

O,O-diethyl phosphorochloridothionate (1.89 g, 0.01 mole) was addeddropwise, at room temperature with stirring, to a suspension ofpotassium 2,4-dimethoxy-s-triazin-6-olate (1.91 g, 0.01 mole) in acetone(30 ml). The mixture was heated under reflux for 1 hr with stirring andthen cooled to room temperature. The reaction mixture was poured intobenzene (150 ml), and the benzene solution was washed with 5% aqueoussodium hydroxide solution and then with water. The benzene layer wasdried over anhydrous sodium sulfate and concentrated under reducedpressure to yield 2.3 g of a pale yellow oily residue. The residue waspurified by column chromatography of silica gel to obtain 1.8 g ofO,O-diethyl O-(2,4-dimethoxy-s-triazin-6-yl)phosphorothionate as acolorless, transparent oil. Refractive index n_(D) ²⁵.0 1,5011

    ______________________________________                                        Elementary analysis:                                                                       C(%)    H(%)      N(%)                                           ______________________________________                                        Calcd. for C.sub.7 H.sub.12 N.sub.3 O.sub.5 PS:                                              29.89     4.27      14.95                                      Found:         29.61     4.47      14.72                                      ______________________________________                                    

EXAMPLE 2 (Compound No. 8)

O-ethyl N-isopropylphosphoramidochloridothionate (2.00 g, 0.01 mole) wasadded dropwise, at room temperature with stirring, to a suspension ofpotassium 2,4-diethoxy-s-triazin-6-olate (2.23 g, 0.01 mole) in acetone(50 ml). The mixture was heated under reflux for 1.5 hr with stirring.The reaction mixture was cooled to room temperature and poured intotoluene (200 ml). The toluene solution was washed with water, and thetoluene layer was dried over anhydrous sodium sulfate and concentratedunder reduced pressure to yield 2.0 g of a pale yellow oily residue. Theresidue was purified by column chromatography on silica gel to give 1.6g of O-ethyl O-(2,4-diethoxy-s-triazin-6-yl) N-isopropylphosphoramidothionate as a pale yellow oil. Refractive index n_(D) ²⁰.01.5030

    ______________________________________                                        Elementary analysis:                                                                       C(%)    H(%)      N(%)                                           ______________________________________                                        Calcd. for C.sub.12 H.sub.23 N.sub.4 O.sub.4 PS:                                             41.14     6.57      16.00                                      Found:         41.51     6.42      16.36                                      ______________________________________                                    

Compounds No. 2 to No. 7 and No. 9 to No. 37 were synthesized in thesame manner as above.

Potassium 2,4-dialkoxy-s-triazin-6-olate, a starting material, wassynthesized according to the method disclosed in K. H. Slotta et al.,Chem. Ber., 60, 303 (1927).

REFERENCE EXAMPLE 1

Cyanuric chloride (30.0 g, 0.163 mole) was dissolved in isopropylalcohol (180 ml), to which powdered sodium hydroxide (19.52 g, 0.488mole) was added thereto at 25° to 30° C. over 30 minutes with stirring.The resulting white suspension was stirred at 30° C. for 2 hours andthen at 40° C. for 1 hour, and filtered. The precipitated sodiumchloride was washed with three 50-ml portions of isopropyl alcohol, andthe filtrate and washings were combined. The powdered potassiumhydroxide (9.13 g, 0.163 mole) was added to the mixture. The mixture wasrefluxed for 1 hour with stirring and concentrated under reducedpressure to yield white crystals. The crystals were washed with coldisopropyl alcohol and then with ether to obtain 37.6 g of potassium4,6-dipropoxy-s-triazin-2-olate as white crystals. Melting point235°-236° C.

PREPARATION EXAMPLE 1

Fifty parts of each of the present compounds (1) to (41) are dissolvedin 40 parts of xylene, to which 10 parts of Sorpol SM-200, anemulsifier, (a registered trade mark of Toho Kagaku Co., a mixture of ananionic surfactant and a nonionic one) are added. The mixture isthoroughly stirred to obtain an emulsifiable concentrate of eachcompound.

PREPARATION EXAMPLE 2

Twenty parts of Sumithion (described hereinbefore) are added to 20 partsof each of the present compounds (1), (2), (3), (5), (12) and (27), towhich 50 parts of xylene and 10 parts of Sorpol SM-200 (described above)are added. The mixture is thoroughly stirred to obtain an emulsifiableconcentrate.

PREPARATION EXAMPLE 3

Forty parts of each of the present compounds (1) to (41) are well mixedwith 5 parts of Sorpol SM-200 (described above), to which 55 parts of300-mesh diatomaceous earth is added. The mixture is well mixed by amortar to obtain a wettable powder of each compound.

PREPARATION EXAMPLE 4

Three parts of each of the present compounds (1) to (41) are dissolvedin 20 parts of acetone, to which 97 parts of 300-mesh talc is added. Themixture is thoroughly mixed by a mortar, and acetone is then removed byevaporation to obtain a dust of each compound.

PREPARATION EXAMPLE 5

Two parts of 3-methylphenyl N-methylcarbamate are added to 2 parts ofeach of the present compounds (6), (14), (16) and (29), and the mixtureis dissolved in 20 parts of acetone. After adding 96 parts of 300-meshtalc thereto, the mixture is treated in the same manner as inPreparation example 4 to obtain a dust.

PREPARATION EXAMPLE 6

To 3 parts of each of the present compounds (1) to (41) are added 5parts of Toyolignin CT (sodium lignosulfonate, a registered trade markof Toyo Spinning Co.) and 92 parts of GSM Clay (a registered trade markof Zieklite Mining Co.), and the mixture is well mixed by a mortar.Thereafter, the mixture is well mixed with water in an amount of 10%based thereon, granulated by means of a granulator and air dried toobtain a granule of each compound.

PREPARATION EXAMPLE 7

To 3 parts of each of the present compounds (1) to (41) are added 5parts of Toyolignin CT (described above) and 92 parts of GSM Clay(described above), and the mixture is well mixed by a mortar.Thereafter, the mixture is well mixed with water in an amount of 10%based thereon, granulated by means of a granulator for fine granuleproduction and air dried to obtain a fine granule of each compound.

PREPARATION EXAMPLE 8

0.2 Part of each of the present compounds (1) and (41) are dissolved inkerosene and made up to 100 parts with kerosene to obtain an oil spray.

PREPARATION EXAMPLE 9

A mixture of 0.2 part of the present compound (17) and 0.1 part oftetramethrin is dissolved in kerosene and made up to 100 parts withkerosene to obtain an oil spray.

PREPARATION EXAMPLE 10

0.2 Part of the present compound (6), 0.2 part of (+)-trans-allethrin, 7parts of xylene and 7.6 parts of deodorized kerosene are well mixed tomake a solution. The solution is filled in an aerosol container. Afterattaching a valve portion to the container, 85 parts of a propellant(liquefied petroleum gas) are charged therein under pressure through thevalve to obtain an aerosol.

PREPARATION EXAMPLE 11

0.2 Part of the present compound (29), 0.1 part of tetramethrin, 11.7parts of deodorized kerosene and 1 part of Atmos 300, an emulsifier, (aregistered trade mark of Atlas Chemical Co., monoglyceride seriesemulsifier) are mixed, and then emulsified with addition of 50 parts ofdistilled water. The emulsion is then filled in an aerosol containertogether with 37 parts of a 3:1 mixture of deodorized butane anddeodorized propane to obtain a water-based aerosol.

EXAMPLE 3

The emulsifiable concentrate obtained in Preparation example 1 wasdiluted 1000 times with water (corresponding to 500 ppm of the activeingredient). On the bottom of a polyethylene cup of 5.5 cm in diameterwas placed a piece of filter paper of the same size, and 0.7 ml of theabove diluted liquor was dropped on the filter paper. Sucrose (30 mg)was placed on the paper as diet. Thereafter, 10 housefly female adults(Musca domestica) were liberated in the cup which was then covered witha lid. After 48 hours, the dead and alive were counted to obtainmortality.

    ______________________________________                                        Test      Mortality  Test         Mortality                                   compound  (%)        compound     (%)                                         ______________________________________                                         (1)      100        (22)         100                                          (2)      100        (23)         100                                          (3)      100        (24)         100                                          (4)      100        (25)         100                                          (5)      100        (27)         100                                          (6)      100        (28)         100                                          (7)      100        (29)          95                                          (8)      100        (30)          95                                          (9)      100        (31)         100                                         (10)      100        (32)         100                                         (11)      100        (33)         100                                         (12)      100        (34)         100                                         (13)      100        (36)         100                                         (14)      100        (37)         100                                         (15)      100        (38)         100                                         (16)      100        (39)         100                                         (17)      100        (40)         100                                         (18)      100        (41)         100                                         (19)      100        No treatment  0                                          (20)      100                                                                 (21)      100                                                                 ______________________________________                                    

EXAMPLE 4

Of the emulsifiable concentrates obtained in Preparation example 1,those containing the present compounds (5), (8), (13), (17) and (32)were diluted 1000 times with water. The diluted liquor was sprayed onrice plants cultivated in a Wagner's pot at a rate of 15 ml per pot.After air-drying, the pot was covered with a wire cage, and 15 smallerbrown planthopper adults (Laodelphax striatellus) were liberatedtherein. In order to examine the residual effect, another group of 15smaller brown planthopper adults were liberated therein 5 days afterspraying. The dead and alive of each group were counted 24 hours afterthe group was liberated in the cage. The mortality is shown in thefollowing table (2 replications).

    ______________________________________                                                    Liberation on  Liberation 5                                       Test        the spraying   days after                                         compound    day            spraying                                           ______________________________________                                         (5)        100            80                                                  (8)        100            73                                                 (13)        100            67                                                 (17)        100            90                                                 (32)         97            70                                                 Diazinon*    97            63                                                 MPMC**      100            50                                                 No treatment                                                                               0              3                                                 ______________________________________                                         *Control: O,Odiethyl                                                          O(2-isopropyl-4-methyl-6-pyrimidinyl)phosphorothionate                        **Control: 3,4Xylyl-N-methylcarbamate                                    

EXAMPLE 5

Five milliliters of each oil spray obtained in Preparation example 9were sprayed on about 100 housefly adults (Musca domestica) per group,according to the Campbel's turntable method [Soap and SanitaryChemicals, Vol. 14, No. 6, 119 (1938)]. The housefly adults were exposedto the descending mist for 10 minutes. By the next day, all thehouseflies could be killed in each case.

EXAMPLE 6

The insecticidal activity on housefly adults (Musca domestica) of eachaerosol obtained in Preparation examples 10 to 11 was tested by theaerosol test method (Soap and Chemical Specialities, Blue Book, 1965)using a (6 ft)³ Peet Grady's chamber. As a result, with each aerosol,more than 80% of the flies could be knocked down 15 minutes afterspraying, and more than 70% of the flies could be killed by the nextday.

EXAMPLE 7

Each dust obtained in Preparation example 5 was applied, by means of aBell jar duster, on potted rice seedlings (diameter of pot, 10 cm),which had elapsed 20 days after sowing, at a rate of 3 kg/10 ares undera pressure of 200 mmHg. After application, the pot was covered with awire cage, and about 20 green rice leafhopper adults (Nephotettixcincticeps) were liberated therein. After 24 hours, the dead and alivewere counted, and it was found that the mortality was 100% in each case.

EXAMPLE 8

Carmine mite female adults (Tetranychus cinnabarinus) were madeparasitic on the leaves of potted kidney bean (primordial stage), at arate of 10-15/leaf, which had elapsed 9 days after sowing, and bred at27° C. for a week in a constant temperature room. Then, numerous carminemites were found to be bred at various growth stages. At this time, a1000-fold aqueous dilute liquor of each emulsifiable concentrateobtained in Preparation example 1 was sprayed on the kidney bean at arate of 10 ml per pot by means of a turn table. Eight days afterspraying, the degree of damage of kidney bean and the number of femaleadults were examined (2 replications).

    ______________________________________                                        Test          Degree of    Number of                                          compound      damage*      female adults                                      ______________________________________                                         (3)          -            0                                                   (5)          -            2                                                   (6)          -            8                                                   (7)          -            0                                                   (8)          -            0                                                  (20)          -            11                                                 (31)          -            21                                                 (36)          -            26                                                 (37)          -            0                                                  Chlorodimeform**                                                                            - to +       27                                                 No treatment  +++          698                                                ______________________________________                                         *The degree of damage was classified as follows:                              -: <10%?                                                                      +: 10-50%                                                                     ++: 50-90%                                                                    +++: >90%                                                                     **Control: N'-(2methyl-4-chlorophenyl)-N,N-dimethylformamidine           

EXAMPLE 9

The egg mass just before hatching of rice stem borer (Chilosuppressalis) was put on rice plants at the tillering stage cultivatedin a Wagner's pot. After 4 days, a granule containing the presentcompound (17) among granules obtained in Preparation Example 6 wasapplied thereto at a rate of 3 kg/10 ares. A 3% Diazinon granule ascontrol was applied at the same rate. Five days after application, therice stem was cut to count the dead and alive of the larvae (2replications). Water in the pot was maintained 3 cm deep throughout thetest period.

    ______________________________________                                        Test compound  Mortality (%)                                                  ______________________________________                                        (17)           100                                                            Diazinon        96                                                            No treatment    4                                                             ______________________________________                                    

EXAMPLE 10

Among emulsifiable concentrates obtained in Preparation example 1, theone containing the present compound (1) was diluted 500 times withwater. Thereafter, to 10 ml of the dilute liquor was added 0.5 ml of aliquor containing numerous nematodes (Panagrellus redivivus). After 48hours, the dead and alive were examined by means of a binocularmicroscope, and it was found that all the nematodes were killed.

What is claimed is:
 1. An organophosphorus ester of the formula,##STR49## wherein R is a C₁ -C₂ alkyl group, R₁ is a C₁ -C₂ alkyl, C₁-C₂ alkoxy, C₁ -C₄ alkylamino, phenyl or phenoxy group, R₂ and R₃, whichmay be the same or different, are each a C₁ -C₅ alkyl or methoxy C₂ -C₃alkyl group and X is an oxygen or sulfur atom.
 2. The compound accordingto claim 1, wherein both R₂ and R₃ are an isopropyl group. 3.O,O-Diethyl O-(2,4-diisopropoxy-s-triazin-6-yl)phosphorothionate of theformula, ##STR50##
 4. O,O-DimethylO-(2,4-diisopropoxy-s-triazin-6-yl)phosphorothionate of the formula,##STR51##
 5. O,O-Diethyl O-(2,4-diisopropoxy-s-triazin-6-yl)phosphate ofthe formula, ##STR52##
 6. O,O-DimethylO-(2,4-diisopropoxy-s-triazin-6-yl)phosphate of the formula, ##STR53##7. An insecticidal, acaricidal or nematocidal composition comprising aninert carrier and as the active ingredient an insecticidally,acaricidally or nematocidally effective amount of a compound accordingto claim
 1. 8. A method for controlling an insect, mite or nematodewhich comprises contacting the insect, mite or nematode with aninsecticidally, acaricidally or nematocidally effective amount of acompound according to claim 1.